RollingBarge.com has built a new style of party barge. As with all of our barges, this new style still floats on 55 gallon plastic drums, however it has an aluminum hull and aluminum sides. The idea is that as the barge accelerates, the bow lifts up and the water inside the bow drains out the stern. With enough propulsion, this new barge should plane and provide significantly higher speeds than the 5mph we see from our current barges.
The main part of the boat is 104 inches wide (8’ 8”). The above picture shows the bow and below shows the stern. In both pictures the boat is upside down.
The main hull is floated by a total of twenty-seven 55 gallon drums and two 30 gallon drums. This provides a total buoyancy of about 13,000lbs.
Above we are adding 1/8” thick aluminum plates to the bottom of the boat frame. This plates are held in place with ¼” aluminum drive rivets every 3”.
“Wings” are designed to bolt to each side of the main body of the barge. These wings are about 27’ long and about 40” wide. Each wing has twelve 55 gallon drums and one 30 gallon drum for a total buoyancy of about 5800lbs. The total buoyancy of all the drums in the barge is about 25,000lbs.
The wing bottoms and sides are skinned in the same 1/8” aluminum plate that is used on the main section of the barge. After the aluminum plate is attached, the barge sections are flipped right side up.
The deck is 5/8” marine plywood. It has a black vinyl backing on the bottom to separate the treated wood from the aluminum and a gray non-slip poly face on the top. The deck is attached with triple coated self-drilling, self-tapping steel screws. The deck is not only a walking surface, but provides significant structural integrity for the entire barge. The upper deck is attached to the main barge section. It is designed to telescope so that the total height can be reduced to 9’ 6”. It is also designed to be sturdy enough to allow the barge to picked up with a forklift from under the upper deck, even with twin 60HP outboards attached. The wings are decked the same as the main barge and then bolted to the main barge with top and bottom ½” bolts every 24”.
The view from the stern. We can easily roll the barge around the shop with a floor jack under each end. The upper story is also decked in 5/8” marine plywood with black vinyl on the bottom, but the top is left bare to accommodate the carpet. Did I mention that it also flies? We lifted the barge up with our four ceiling hosts so we could set it on the trailer. With the barge on the trailer it is time to mount the outboard motors and the slide. Seams of deck are added to fill the gap between the wings and the main barge. Also, a stern wall is added to block the passengers from the noise of the motors. With all the gates in place, we are ready for our first test. At 15’ 2” wide, she’s a bit of a squeeze through our shop doors… One plane she generates almost no wake. Our maximum speed was 24mph with 11 pitch props and three people on board.
The gentleman on the right is Tullio Celano, the Naval Architect and Structural Engineer that helped design the barge. He was present for our maiden voyage and was very pleased with the look of our vessel. On our first tests we found that we could plane using 11 pitch props with three people on board. But any more people and she would not plane. Our biggest problem was that the props would cavitate at slow speeds and would not allow us to use more than about 50% throttle.
The motor shipped to us by Iguana was 5 inches shorter than our motor. We had temporarily adjusted the transom to makeup 4” of this difference, but that was not enough to eliminate the cavitation.
We then rebuilt the transom and extended the short motor. The result was that the long motor was lowered 2.25” and the short motor was now the same as the long motor. The top caviation plate on both motors is a good three inches below the hull.
At the recommendation of Dwayne, a mechanic at Iguana Watersports, we built some Cavitation Plate Extensions show above, but these only made the cavitation worse.
We removed the Cavitation Plate Extensions and tested with some 10 pitch propellers that are “cupped” which is supposed to reduce cavitation. The cavitation was reduced significantly, but the new top speed was only 8.2mph. We did not attach a tachometer, but it appeared to us that both motors were running at full rpm and the push with the 10 pitch props was just not quite enough to get us on plane. We tested with 10 people on board weighing a total of about 1450 lbs.
With this same load of 10 people we switched to two 11 pitch props that are not cupped. At speeds below 10mph these props still cavitated at anything above about 50% throttle, but they were enough to put the boat on plane and give us 21+mph with our 10 person (1450lb) load.
Our next step is to test with 11 pitch “cupped” props. We will keep you posted. PCK